title: Patient-controlled analgesia with inhaled methoxyflurane versus conventional endoscopist-provided sedation for colonoscopy: a randomized multicenter trial.
abstract: OBJECTIVE
  Inhaled methoxyflurane (Penthrox, Medical Device International, Melbourne, Australia) has been used extensively in Australasia (Australia and New Zealand) to manage trauma-related pain. The aim is to evaluate the efficacy, safety, and outcome of Penthrox for colonoscopy.
  
  
  METHODS
  Prospective randomized study.
  
  
  METHODS
  Three tertiary endoscopic centers.
  
  
  METHODS
  Two hundred fifty-one patients were randomized to receive either Penthrox (n = 125, 70 men, 51.4 ± 1.1 years old) or intravenous midazolam and fentanyl (M&F; n = 126, 72 men, 54.9 ± 1.1 years old) during colonoscopy.
  
  
  METHODS
  Discomfort (visual analogue scale [VAS] pain score), anxiety (State-Trait Anxiety Inventory Form Y [STAI-Y] anxiety score), colonoscopy performance, adverse events, and recovery time.
  
  
  RESULTS
  Precolonoscopy VAS pain and STAI-Y scores were comparable between the 2 groups. There were no differences between groups in (1) pain VAS or STAI Y-1 anxiety scores during or immediately after colonoscopy, (2) procedural success rate (Penthrox: 121/125 vs M&F: 124/126), (3) hypotension during colonoscopy (7/125 vs 8/126), (4) tachycardia (5/125 vs 3/126), (5) cecal arrival time (8 ± 1 vs 8 ± 1 minutes), or (6) polyp detection rate (30/125 vs 43/126). Additional intravenous sedation was required in 10 patients (8%) who received Penthrox. Patients receiving Penthrox alone had no desaturation (oxygen saturation [SaO(2)] < 90%) events (0/115 vs 5/126; P = .03), awoke quicker (3 ± 0 vs 19 ± 1 minutes; P < .001) and were ready for discharge earlier (37 ± 1 vs 66 ± 2 minutes; P < .001) than those receiving intravenous M&F.
  
  
  CONCLUSIONS
  Inhaled Penthrox is not yet available in the United States and Europe.
  
  
  CONCLUSIONS
  Patient-controlled analgesia with inhaled Penthrox is feasible and as effective as conventional sedation for colonoscopy with shorter recovery time, is not associated with respiratory depression, and does not influence the procedural success and polyp detection.
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: Nam Q
authors.initials: NQ
authors.lastname: Nguyen
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: Leanne
authors.initials: L
authors.lastname: Toscano
authors.affiliation: Colo-Rectal Surgical Unit, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Lawrence
authors.affiliation: Colo-Rectal Surgical Unit, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: James
authors.initials: J
authors.lastname: Moore
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Holloway
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: Dylan
authors.initials: D
authors.lastname: Bartholomeusz
authors.affiliation: Department of Gastroenterology, The Queen Elizabeth Hospital, Adelaide, South Australia.
authors.forename: Ilmars
authors.initials: I
authors.lastname: Lidums
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia; Department of Gastroenterology, Lyell McEwin Health Service, Adelaide, South Australia.
authors.forename: William
authors.initials: W
authors.lastname: Tam
authors.affiliation: Department of Gastroenterology, The Queen Elizabeth Hospital, Adelaide, South Australia.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Roberts-Thomson
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: Venkataswamy N
authors.initials: VN
authors.lastname: Mahesh
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Debreceni
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia.
authors.forename: Mark N
authors.initials: MN
authors.lastname: Schoeman
mesh_terms: D000280:Administration, Inhalation; D016058:Analgesia, Patient-Controlled / Q000009:adverse effects; D000762:Anesthesia Recovery Period; D018685:Anesthetics, Inhalation / Q000008:administration & dosage* / Q000009:adverse effects; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000009:adverse effects; D001007:Anxiety / Q000175:diagnosis; D003113:Colonoscopy / Q000379:methods*; D016292:Procedural Sedation; D005260:Female; D005283:Fentanyl; D006801:Humans; D008297:Male; D008733:Methoxyflurane / Q000008:administration & dosage* / Q000009:adverse effects; D008874:Midazolam; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010147:Pain Measurement; D017060:Patient Satisfaction
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008733:Methoxyflurane; D008874:Midazolam; D010100:Oxygen; D005283:Fentanyl
keywords: IV; M&E; STAI-Y; State-Trait Anxiety Inventory Form Y; VAS; intravenous; midazolamand fentanyl; visual analogue scale